Method for forming an antifuse element with electrical or optical programming

Abstract

A programmable antifuse element comprising adjacent bodies of germanium and aluminum or aluminum alloy form forming a low resistance connection of good mechanical and thermal properties when heated to a temperature where alloying of the aluminum and germanium occurs. Heating for the purpose of programming the antifuse element can be done by electrical resistance heating in the germanium, which may be doped to achieve a desired resistance value, or by laser irradiation. Due to the high resistance of intrinsic or lightly doped germanium, a resistance change ratio of greater than 10,000:1 is achieved.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows: 
     
       1. A method of fabricating a programmable connection including the steps of depositing a body containing aluminum,   depositing a body of germanium adjacent said body of aluminum, and   selectively heating at least a portion of each of said bodies of germanium and aluminum to a temperature in excess of approximately 420° C. to cause diffusion of said portion of each of said bodies of germanium and aluminum.   
     
     
       2. A method as recited in claim 1, wherein said heating step is performed with a carbon dioxide laser. 
     
     
       3. A method as recited in claim 1, including the further step of forming a via and wherein said step of depositing said body of germanium and said step of depositing said body containing aluminum form bodies within said via. 
     
     
       4. A method as recited in claim 1, including the further step of depositing a body of tungsten.   
     
     
       5. A method as recited in claim 1, including the further step of forming a via and wherein said step of depositing said body of germanium and said step of depositing said body containing aluminum form bodies within said via. 
     
     
       6. A method as recited in claim 5, including the further step of depositing a body of tungsten.   
     
     
       7. A method of fabricating a programmable connection including the steps of depositing a body containing aluminum,   depositing a body of germanium adjacent said body of aluminum,   doping said body of germanium to reach a resistance value range suitable for electrical resistance heating, and   selectively alloying at least a portion of said body of germanium with at least a portion of said body containing aluminum by electrical resistance heating of said body of germanium.   
     
     
       8. A method as recited in claim 7, including the further step of depositing a body of tungsten.   
     
     
       9. A method as recited in claim 7, including the further step of forming a via and wherein said step of depositing said body of germanium and said step of depositing said body containing aluminum form bodies within said via. 
     
     
       10. A method as recited in claim 9, including the further step of depositing a body of tungsten.